A packaging structure is known in which a first substrate including a copper terminal and a second substrate including a copper terminal are stacked, and the copper terminals are directly bonded (so-called a Cu—Cu direct bonding).
For Cu—Cu direct bonding, a method in which surfaces of the copper terminals to be bonded are activated and in which the surfaces of the copper terminals are bonded under vacuum pressure (room temperature bonding, SAB: Surface Activated Bonding), a method in which the surfaces of the copper terminals are grinded by a tool grinder or the like and in which the copper terminals are bonded under reducing atmosphere at vacuum pressure, a bonding method by generating metal salt or the like, is used.
Here, before performing the Cu—Cu direct bonding, it is necessary to align the copper terminals to be bonded. For a method of aligning the copper terminals before bonding, a method is known that uses an apparatus including an alignment device provided in a vacuum chamber, for example.
Patent Document 1: Japanese Laid-open Patent Publication No. 2015-008228
However, according to the above described alignment method, there is a problem that corrosion of the alignment device occurs in addition to a problem that the apparatus that includes the alignment device is expensive.